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2014/01/23

An anti-submarine strategy which doesn't care about their stealth

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(Warning; long text, no eye candy.)

I was involved in a discussion at Think Defence about maritime patrol aircraft (MPA) and after becoming annoyed I issued a kind of challenge: I asked

Can you imagine an anti-SSK doctrine which renders the submarine’s stealth -its greatest strength- largely irrelevant?

It was a kind of trick question and I got the fully anticipated

No, of course not.

kind of answer.

Well, of course it's possible to devise an anti-SSK doctrine and strategy which renders the enemy submarines' stealth irrelevant. You would never get this idea as long as you're locked into a tunnel vision on big ticket hardware and direct attack, of course.

The idea that in order to defeat a submarine you need to hit (destroy) it is simplistic and shouldn't be more than the very first, intuitive and primitive idea. You should keep thinking afterwards, including a search of military history, if you want to come to an idea of anti-submarine warfare that's worth being uttered.

Let's go full abstract for a while. The submarine, how does it turn into a problem?

First there's a base. The submarine are here and prepare for a patrol.

Then there's the platform (the submarine) on patrol.

Next, there are munitions moving towards

targets.

Base-platform-munitions-targets.

It's a mistake to apply a tunnel vision on the platform alone.

Here's a list of imaginable counters to a submarine threat (my work of about ten minutes, not comprehensive):

issue of return and radio silence order by ELF once and if hostile ELF emitters were destroyed and codes known through intelligence

Note how only a single line was about the most obvious, intuitive and superficial action; an attack on the sub at sea.

This list shows that you can indeed do a lot about the bases - and thus maybe keep a couple hostile submarines from ever going on a wartime patrol. More reliably, taking out bases and replenishment ships may limit the submarines to a single patrol. In fact, most countries have so very small inventories of munitions that they could probably not reload all of their submarines at least once anyway. This is in part a consequence of human fallibilities and the primacy of deterrence over warfighting and in part it's an after-effect of the Cold War when almost nobody expected a second patrol for any NATO or Warsaw Pact submarine in case of World War 3. Times have changed, and being able to deny a 2nd or 3rd patrol may easily equate cutting the submarine threat by 60 or 70%. So call in the bombers. Offensive minelaying serves the same purpose; less patrols.

Some other mentioned actions are meant to make contacts less likely, and especially so under unfavourable conditions. LF active sonar has fine ranges, but hardly enough range to prevent attacks by submarines altogether. Submarine commanders who are aware of LF sonar qualities against their boat will tend to limit the risk - this means a preference for combat under favourable circumstances or the launch of ammunitions from long-enough ranges. Peacetime exercises task submarines to attack targets and the submarines engage accordingly, and especially SSNs are often having a hard time being forced into risky attack by such orders. In wartime, tactics may be different and someone under the great impression of peacetime exercises and experiments may easily misunderstand the interaction.

Another set of measures was meant to reduce the effectiveness of the munitions by addressing their lethality after launch - irrespective of the launch position. Torpedoes and submarine-launched missiles are guided munitions. Every critical component has a probability to fail, and items with dependence on many critical components have an accumulated and often astonishingly high chance to fail. Peacetime testing often fails to discover even the most horrendous problems. Torpedoes and missiles tend to have impressive technical failure rates; ranging from less than 5% to about 70% historically. Yet even newly-made items of a perfectly mature munition design with decades of service and testing will in practice fail you a lot:
You can test your munitions against friendly ships and friendly countermeasures (technical and tactical), but only wartime delivers the true test; against hostile ships and hostile countermeasures. We didn't have much of this for anti-ship missiles and none for post-WW2 torpedoes. It's akin to F-22 Raptor fighters winning against Western fighters in simulated fights; who cares? It's not the Western air forces which have prepared to counter the F-22 for a quarter century by now.

I personally think a hit probability of 20% for every torpedo which leaves port is a realistic guess. The ph for a torpedo hit on a high value target (CV, LPD, DDG, FFG, supertanker et cetera) may easily be 5% or less if civilian low-value ships are being abused as decoys (again, ph per torpedo which left port with the boat).

I suppose you know the periscope photo trophies of 'sunk' carriers? Well, in wartime against a competent navy such photos should not be possible. There could be long container ship to the left and another one to the right (no, I won't look up the English translation for the correct nautical terms) and two small ones in the wake of the carrier. A torpedo salvo's odds of taking the carrier out of action would be very disappointing. The commander might actually choose to sink two DDGs instead - except that these probably have plenty decoy boats in action as themselves.

So this was already about the fourth item, the targets. Even munitions which hit may actually yield disappointments as a consequence of applied tactics.

What didn't I mention much so far? Oh yes, killing the sub. Well, to build a navy to destroy subs at sea may actually be a stupid idea. One reason is that targets are plenty, thus assets to protect them would need to be plenty - and high quality (high cost), or else they might be ineffective. Another reason is that the oceans are huge, so you would need terribly many assets - again high quality and high cost - to hunt submarine there.

How exactly could this be a reasonable approach if maybe the threat is only half a dozen submarines? Or maybe it's a dozen, or two dozen - but you would need many dozen ships and many dozen rotary and fixed wing aircraft if you insisted that destroying submarines is the centrepiece or even only important in your strategy.

And let's not forget the hostile submariners may get lucky and have one or two advances on their side, devaluing your huge sub killer force. There's no guarantee that you stay ahead of them if you focus on the direct approach, after all.

So is it possible to devise an anti-SSK doctrine which renders their
stealth largely irrelevant? Yes, of course, it is. In theory you don't
need to detect them in order to defeat them, ever. They're no ramming boats. Their
lethality depends on their munitions (usually only one to three
different types), the quantity of munitions is limited and later patrols
are only possible if certain conditions are met. You can address the
SSK threat without hunting SSKs explicitly. You certainly don't need
MPAs against them. MPAs are a choice, and I suppose the odds of MPAs being or staying ahead the curve in relation to hostile great power subs are unsatisfactory.

I suppose a very typical -if not unavoidable- counter to my case is that the losses incurred this way - 20% hits, for example - would be unacceptable.*

Let's think about this rationally. A competent hostile navy will sink ships anyway, even if you ruin your country fiscally building an anti-submarine warfare (ASW) fleet and hordes of MPAs. Compare the costs of a comprehensive kill-oriented (and kill-dependent) ASW approach both in procurement and in operations costs to an ASW approach in which the focus is rather on addressing replenishment and munitions, and in which a couple more 'targets' are built in order to have enough of them left after the subs on their first patrol struck a few times.

An actual calculation of which approach is better would depend on a great many unknown variables, though a very small threat submarine fleet should clearly favour my approach, while a very vulnerable (noisy) submarine fleet would clearly favour the conventional 'kill the subs at sea' approach. Quel surprise; Soviet subs were noisy when the now dominant approach to ASW was coined!

Those who were thoroughly indoctrinated by navies in their orthodox doctrine and those who love hardware emotionally or for business reasons will almost inevitably think now that I'm batshit crazy. I know that, but I'm independent, don't get paid for writing on military affairs, wasn't solidly indoctrinated by a navy and I maintained the ability to think about stuff on an abstract level, with little emotional attachment to the conventional wisdom and doctrine.How could anyone tell this apart from batshit crazy nowadays?

*: I didn't bother writing this piece in an order and in a wording to convince readers fully. A certain cognitive dissonance between what's believed so far and the points herein is intentional. Those who have already formed an opinion will either grow old and still believe as elderly people in 50 years old ideas or they need to overcome cognitive dissonance at some point and embrace different thoughts. Nobody needs to be convinced by this blog text, but at least some readers should keep in mind that the way to grow is to stretch one's old skin.

Yes. It's nothing spectacular, but it requires to break the tunnel vision on the direct approach and some modesty.The easiest idea is to kill all subs before they can open fire. It's also the hardest in reality.

The ability to effectively hunt subs is a very-nice-to-have, but not a necessity for operational and strategic success in naval warfare.